The present disclosure is related to sorption cooling of a component of a downhole tool. One way to cool a device downhole includes evaporating a refrigerant stored on the downhole tool from a liquid phase to a gaseous phase. Once the evaporated refrigerant has cooled the component, it is generally stored at a desiccant or other solid body which adsorbs the gas-phase refrigerant in the downhole tool until the tool is retrieved to the surface, at which time the refrigerant is removed and/or the refrigerant is desorbed from the desiccant by thermal heating. However, once the desiccant becomes saturated with refrigerant, the cooling operation ends. It is generally time-efficient and cost-efficient to regenerate the desiccant downhole by desorbing the evaporated refrigerant from the desiccant downhole rather than bringing the downhole tool to the surface. Known methods of desiccant regeneration include heating of the desiccant, reducing pressure within a volume of the desiccant, and purging the desiccant using a purge gas. However, due to temperatures and pressures experienced at downhole environments as well as operational considerations, the use of these methods is limited. The present disclosure provides a method and apparatus for desorbing refrigerant gas from a desiccant in a downhole cooling system.